Multi VDOM mode and HA
Multi VDOM mode supports all FortiGate 7000E HA configurations described in FortiGate 7000E high availability, including standard FGCP HA, virtual clustering, FGSP, standalone configuration synchronization, and VRRP.
To successfully form an FGCP HA cluster, both FortiGate 7000Es must be operating in the same VDOM mode (Multi or Split-Task). You should change both FortiGate 7000Es to the VDOM mode that you want them to operate in before configuring HA. To change the VDOM mode of an operating cluster, you need remove the backup FortiGate 7000E from the cluster, switch both FortiGate 7000Es to the other VDOM mode and then re-form the cluster. This process will cause traffic interruptions.